Combined Scale Factor Helper
A free, browser-based calculator. Runs entirely in your browser — no sign up, nothing stored.
100% FreeRuns in your browserIntermediate
Enter Values
Enter your values and press Calculate to see results.
How to use this calculator
- Enter the grid (point) scale factor.
- Enter the ground height above the ellipsoid.
- Press Calculate for the combined scale factor.
How it works
Combined scale factor = grid scale factor × elevation factor, where the elevation factor = R ÷ (R + height). Multiply a ground distance by this to get the grid distance.
Worked example
Grid 0.99960, height 400 m. Elevation factor ≈ 0.99994, combined ≈ 0.99954.
Frequently asked questions
Ground to grid or grid to ground?
Multiply ground distance by the combined scale factor to get grid distance; divide to go the other way.
Related tools
Tip: Enter any known values to calculate the remaining results.
All calculations run in your browser. Your inputs are never saved or transmitted.